Decline of the Great Salt Lake

Author

Joshua Gladwell

Published

May 5, 2023

Figure 1: 3D model of the Great Salt Lake, circa April 2023. The model was designed by innovatively merging elevation and bathymetry data to accurately represent the terrain both above and below the lake’s water. The Union Pacific railroad causeway can be seen stretching roughly 20 miles across the width of the lake, splitting the North Arm (darker color) from the South Arm (brighter color).

Introduction

Utah’s Great Salt Lake is rapidly declining due to agricultural overconsumption, demands of the growing population, and climate change.1 In addition to failing a long-standing ecosystem,2 the decline also exposes toxic elements such as arsenic and mercury on the dried-up lakebed to wind that could carry the chemicals into the highly-populated surrounding areas.3 It’s a serious concern that poses severe consequences for the state of Utah.

Researchers, legislators, and others have posed many solutions to save the lake. However, the lake itself maintains a highly complicated balance of systems, which in turn complicates the possible solutions. For example, in 1959, Union Pacific built a railroad causeway across the width of the lake (from east to west), splitting the lake into a North Arm and a South Arm. Figure 1 shows the color difference between the lighter South Arm and the darker, almost red North Arm. Because the North Arm averages between 26-30% salinity compared to the 12-15% salinity of the South Arm,4 the North Arm contains high populations of halophiles and algae, giving it its reddish color. Some have suggested cutting off the already limited flow between the North Arm and South Arm as a solution to save the lake, but others view this as a way to prolong the inevitability of the lake’s decline.5 Other proposed solutions have included use of artificial clouds, pipelines, and groundwater extractions, but most scholars agree that the only viable solution is to establish legislation that enacts major water conservation efforts.6 As solutions are discussed among researchers and legislators, some may argue that any efforts are already too late. The lake’s water loss has accelerated since 2020 and if no action is taken to stop the accelerated rate, the lake is projected to dry up by 2028.7

History of Great Salt Lake

In order to understand the significance of the lake’s current decline, it is important to understand several aspects of the lake’s history.

Figure 2 below illustrates the Great Salt Lake’s recorded water elevation in feet above NGVD 1929 since 1966. At first glance, one may wonder why the low water elevation of today is such a concern when it appears to have had the same level in the 1960s. At this time, Great Salt Lake was indeed facing a similar fate when several years of unprecedented rainfall happened to save the lake. The bottom plot of Figure 2 features the change in water elevation in 1986, one of the highest-elevation years for the lake. This is a key year in that it brought flooding to the lake and showed the world what the lake could look like at a modern-day full capacity. However, archaeological evidence suggests that this magnitude of rainfall hadn’t occurred in the Salt Lake Valley for roughly one thousand years,8 underscoring the need to pursue acts of conservation rather than waiting for rain.9

Comparing the water level from the 1960s to now, it is also important to understand that the Great Salt Lake is a relatively shallow lake with a maximum depth of roughly 33 feet.10 This makes it especially sensitive to small changes in its water levels. Furthermore, one should bear in mind the natural underwater shape of lakes. Lakes are generally bowl-shaped, which is significant in that the difference between a foot of water elevation represents much more water volume at higher levels than at lower levels. Compare this, for example, to a box-shaped swimming pool, where the difference in a foot of water elevation at the bottom of the pool versus the top of the pool is roughly the same. Thus, changes in water elevations at lower levels of the lake are far more difficult to ameliorate than elevation changes at higher levels.

One of the most important elements of Figure 2 is the seasonality shown in the top plot. Each summer, the water elevation drops due to high evaporation in the dry season, followed by high precipitation in the winter (in the form of snow). As the snow melts going into spring, the runoff usually refills the lake each year. In the periods of time when the lake is in decline, it is usually declining as a result of less runoff water refilling the lake in the spring months. This supports the claims that overconsumption of runoff water is the leading factor in the lake’s decline.11

Figure 2: Interactive line plots illustrating the change in Great Salt Lake’s water elevation (ft above NGVD 1929). The top plot shows all recorded change, while the bottom plot shows change over the course of a year. Official measurements on the lake’s water levels began April 15th, 1966. Measurement frequency switched from bimonthly to daily on October 1st, 1989. Also included are two reference lines. The maroon line (set at 4,196.36 ft elevation)12 indicates the estimated lake elevation at which toxic dust and sediment are no longer covered by water, thus becoming vulnerable to winds potentially carrying the chemicals into the surrounding communities. The blue line (set at 4,191 ft)13 indicates the estimated lake elevation at which the salinity rises beyond that of a healthy environment for brine shrimp.

Figure 2 also features two key elements in the story of Great Salt Lake’s decline. Years of pollution from local factories have led to high levels of toxic chemicals such as arsenic and mercury in the lake. As the lake shrinks below roughly 4,196 ft,14 leaving these chemicals in the dry dust that remains, sediment-filled winds threaten to inflict severe health risks on the local population.

The lake’s decline also bears significance for a broad ecosystem. The Great Salt Lake has historically sustained a $60 million brine shrimp industry,15 but as the lake shrinks to below 4,191 ft in water elevation, an increased concentration of salinity threatens the brine shrimp ecosystem.16

Dust and Sediment

Perhaps the most urgent concern for the decline of the Great Salt Lake is the exposure of toxic chemicals it introduces to the nearby community. As the lake continues to shrink, toxic chemicals such as arsenic are being exposed to wind, which can carry them into the surrounding areas where many people reside. This is a serious concern as exposure to high levels of arsenic can cause health problems such as skin lesions, cancer, and cardiovascular disease.

The animation in Figure 3 demonstrates the process of this phenomenon very clearly.

Figure 3: 3D model of the Great Salt Lake, illustrating the water elevation for every month for which there is recorded data (April 1966 - April 2023). As the water elevation decreases, large areas of land become exposed to open air–no longer submerged underwater. Pay particular attention to the lakebed exposure on the southeast and northwest ends of the lake. Without water to cover the toxic chemicals sitting on the lakebed, they run the risk of being carried into the surrounding community by the wind.

Much of the lakebed is already exposed to the open air at the time of writing and has been exposed for the last several years. Some evidence17 suggests that arsenic, one of the toxic chemicals high in the Great Salt Lake, has already spread to outlying neighborhoods in the form of dust and sediment.

Figure 4: Bubble map of arsenic levels around the Salt Lake Valley, circa 2018-19. Some sites contained multiple samples; thus, multiple bubbles are shown in same locations. The spread of high arsenic samples shows that arsenic-ridden dust has already spread from the lake.

Figure 4 shows that levels of arsenic in the exposed dust near the lake is roughly equal to the levels of arsenic in neighborhoods miles away from the lake. For example, a sample at the “Lehi residential area” site recorded arsenic levels of 26.16 PPM, roughly equal to the 25.04 PPM of arsenic recorded at the “North playa near UT Test and Training Range” site much closer to the lake. This suggests that the spread of these chemicals may have already begun, and that the worst may be yet to come.

Brine Shrimp

Aside from posing a public health concern, the decline of the Great Salt Lake has significant implications for the brine shrimp population and the entire ecosystem that depends on it. Brine shrimp are an important part of the lake’s food chain and play a critical role in maintaining the lake’s ecosystem.

Brine shrimp are a unique species that thrive in the high salinity waters of the Great Salt Lake. They are an essential source of food for many bird species, including the American Avocet, Wilson’s Phalarope, and the Eared Grebe, which rely heavily on brine shrimp during their migrations.

The decline in the lake’s water level has led to a reduction in the brine shrimp population, which has a ripple effect on the entire ecosystem. Birds that rely on brine shrimp as a food source may have to find alternative sources of food, or they may not be able to sustain their populations, leading to a decline in bird species diversity. Additionally, the decline of brine shrimp populations can affect the lake’s water quality, as they play a role in consuming organic matter in the water, helping keep the lake clean.

Furthermore, brine shrimp are commercially significant. They are harvested from the lake and sold as food for fish farms and aquariums. The decline in the brine shrimp population has led to a reduction in the number of shrimps that can be harvested, which affects the livelihoods of those who depend on this industry.

Figure 5 illustrates the reality that a smaller lake yields fewer brine shrimp. Since 2020, the number of young brine shrimp (juveniles and nauplii) in the lake has steadily declined. This decline corresponds to a significant period of decline in the lake’s water elevation, resulting in higher salinity levels in the lake which are unfit for brine shrimp habitation (see Figure 2).

Figure 5: Linked view of brine shrimp sample counts for every recorded brine shrimp harvest from 2010-2023.18 Select a section of the line plot on the left to view the average brine shrimp counts for the selected harvest on the right. Cysts are defined as dormant brine shrimp eggs. Nauplii are defined as larva brine shrimp, which are younger than juveniles. During the 2010-11 harvest, nauplii were very highly concentrated in the lake (at about 3.6 per liter of lake water). Today, (in the 2022-23 harvest), they are far more scarce occurring at about 0.25 per liter of lake water.

The story of Figure 5 suggests the impending fall of several important systems that the Great Salt Lake sustains. A complete loss of the brine shrimp in the Great Salt Lake would trigger the death of thousands of migratory birds, erase countless jobs, and negatively impact the local economy.

Conclusion

The Great Salt Lake is at risk of drying up due to factors such as agricultural overconsumption, population growth, and climate change. Two of the major ramifications to the lake’s decline are exposure of toxic elements to the nearby population and the loss of environmental and economic systems supported by the lake’s brine shrimp. Researchers, legislators, and others have proposed many solutions to save the lake, but the highly complicated balance of systems in the lake has made this challenging. Establishing legislation that enacts major water conservation efforts is seen as the most viable solution, but this process must begin soon in order to ensure the lake’s survival.

Yearly Data

Below is an interactive data table to view yearly data for Great Salt Lake’s water elevation.

Footnotes

  1. Lozada, G. A. Agricultural Water Use, Hay, and Utah’s Water Future. 26 https://content.csbs.utah.edu/~lozada/Research/UtahAgWaterUseHay.docx (2022).↩︎

  2. Baxter, B. K. & Butler, J. K. Great Salt Lake biology: a terminal lake in a time of change. (2020).↩︎

  3. Putman, A. L., Jones, D. K., Blakowski, M. A., DiViesti, D., Hynek, S. A., Fernandez, D. P., & Mendoza, D. (2022). Industrial particulate pollution and historical land use contribute metals of concern to dust deposited in neighborhoods along the Wasatch Front, UT, USA. GeoHealth, 6, e2022GH000671. https://doi.org/10.1029/2022GH000671↩︎

  4. GSLEP. About the Great Salt Lake. https://wildlife.utah.gov/gslep/about.html. (2022).↩︎

  5. Williams, Terry Tempest, and Fazal Sheikh. “I Am Haunted by What I Have Seen at Great Salt Lake.” The New York Times, The New York Times, 25 Mar. 2023, https://www.nytimes.com/2023/03/25/opinion/great-salt-lake-drought-utah-climate-change.html.↩︎

  6. Abbott, Benjamin & Baxter, Bonnie & Busche, Karoline & Freitas, Lynn & Frei, Rebecca & Gomez, Teresa & Karren, Mary & Buck, Rachel & Price, Joseph & Frutos, Sara & Sowby, Robert & Brahney, Janice & Hopkins, Bryan & Bekker, Matthew & Bekker, Jeremy & Rader, Russell & Brown, Brian & Proteau, Mary & Carling, Greg & Belmont, Patrick. (2023). Emergency measures needed to rescue Great Salt Lake from ongoing collapse. 10.13140/RG.2.2.22103.96166.↩︎

  7. Abbott, Benjamin & Baxter, Bonnie & Busche, Karoline & Freitas, Lynn & Frei, Rebecca & Gomez, Teresa & Karren, Mary & Buck, Rachel & Price, Joseph & Frutos, Sara & Sowby, Robert & Brahney, Janice & Hopkins, Bryan & Bekker, Matthew & Bekker, Jeremy & Rader, Russell & Brown, Brian & Proteau, Mary & Carling, Greg & Belmont, Patrick. (2023). Emergency measures needed to rescue Great Salt Lake from ongoing collapse. 10.13140/RG.2.2.22103.96166.↩︎

  8. Simms, S. 2002 Ancient American Indian Life in the Great Salt Lake Wetlands: Archaeological and Biological Evidence. Co-author with M. Stuart. In Great Salt Lake, Utah 1980 Through 1998, edited by J. Wallace Gwynn, Utah Geological Survey Publications, Salt Lake City. in (2018).↩︎

  9. Abbott, Benjamin & Baxter, Bonnie & Busche, Karoline & Freitas, Lynn & Frei, Rebecca & Gomez, Teresa & Karren, Mary & Buck, Rachel & Price, Joseph & Frutos, Sara & Sowby, Robert & Brahney, Janice & Hopkins, Bryan & Bekker, Matthew & Bekker, Jeremy & Rader, Russell & Brown, Brian & Proteau, Mary & Carling, Greg & Belmont, Patrick. (2023). Emergency measures needed to rescue Great Salt Lake from ongoing collapse. 10.13140/RG.2.2.22103.96166.↩︎

  10. GSLEP. About the Great Salt Lake. https://wildlife.utah.gov/gslep/about.html. (2022).↩︎

  11. Lozada, G. A. Agricultural Water Use, Hay, and Utah’s Water Future. 26 https://content.csbs.utah.edu/~lozada/Research/UtahAgWaterUseHay.docx (2022).↩︎

  12. Putman, A. L., Jones, D. K., Blakowski, M. A., DiViesti, D., Hynek, S. A., Fernandez, D. P., & Mendoza, D. (2022). Industrial particulate pollution and historical land use contribute metals of concern to dust deposited in neighborhoods along the Wasatch Front, UT, USA. GeoHealth, 6, e2022GH000671. https://doi.org/10.1029/2022GH000671↩︎

  13. Penrod, Emma. “One of the World’s Strangest - and Most Critical - Fisheries Is in Serious Danger: Ambrook Research.” Ambrook, Ambrook, 31 Aug. 2022, https://ambrook.com/research/sustainability/great-salt-lake-utah-artemis-brine-shrimp-aquaculture-drought#.↩︎

  14. Putman, A. L., Jones, D. K., Blakowski, M. A., DiViesti, D., Hynek, S. A., Fernandez, D. P., & Mendoza, D. (2022). Industrial particulate pollution and historical land use contribute metals of concern to dust deposited in neighborhoods along the Wasatch Front, UT, USA. GeoHealth, 6, e2022GH000671. https://doi.org/10.1029/2022GH000671↩︎

  15. GLSEP. “Brine Shrimp Harvests.” Utah Division of Wildlife Resources, 20 Mar. 2023, https://wildlife.utah.gov/gslep/harvests.html.↩︎

  16. Penrod, Emma. “One of the World’s Strangest - and Most Critical - Fisheries Is in Serious Danger: Ambrook Research.” Ambrook, Ambrook, 31 Aug. 2022, https://ambrook.com/research/sustainability/great-salt-lake-utah-artemis-brine-shrimp-aquaculture-drought#.↩︎

  17. Putman, A. L., Jones, D. K., Blakowski, M. A., DiViesti, D., Hynek, S. A., Fernandez, D. P., & Mendoza, D. (2022). Industrial particulate pollution and historical land use contribute metals of concern to dust deposited in neighborhoods along the Wasatch Front, UT, USA. GeoHealth, 6, e2022GH000671. https://doi.org/10.1029/2022GH000671↩︎

  18. GLSEP. “Brine Shrimp Harvests.” Utah Division of Wildlife Resources, 20 Mar. 2023, https://wildlife.utah.gov/gslep/harvests.html.↩︎